Commit 8e2929c6 authored by Ashok Raj's avatar Ashok Raj Committed by Aichun Shi
Browse files

platform/x86/intel/ifs: Add an entry rendezvous for SAF 

mainline inclusion
from mainline-v6.9-rc1
commit ad630f5d92717632a15e1d0b92e5421e6eac7c8d
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/IASVRQ
CVE: N/A
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad630f5d92717632a15e1d0b92e5421e6eac7c8d



-------------------------------------

The activation for Scan at Field (SAF) includes a parameter to make
microcode wait for both threads to join. It's preferable to perform an
entry rendezvous before the activation to ensure that they start the
`wrmsr` close enough to each other. In some cases it has been observed
that one of the threads might be just a bit late to arrive. An entry
rendezvous reduces the likelihood of these cases occurring.

Add an entry rendezvous to ensure the activation on both threads happen
close enough to each other.

Intel-SIG: commit ad630f5d9271 platform/x86/intel/ifs: Add an entry rendezvous for SAF
Backport to support IFS(In Field Scan) SBAF(Structural Based Functional Test at Field)

Signed-off-by: default avatarAshok Raj <ashok.raj@intel.com>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20240125082254.424859-6-ashok.raj@intel.com


Reviewed-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
[ Aichun Shi: amend commit log ]
Signed-off-by: default avatarAichun Shi <aichun.shi@intel.com>
parent 28b7f9b2

drivers/platform/x86/intel/ifs/runtest.c

+26 −22
Original line number Diff line number Diff line
@@ -140,6 +140,29 @@ static bool can_restart(union ifs_status status) 
	return false;

}



#define SPINUNIT 100 /* 100 nsec */

static atomic_t array_cpus_in;

static atomic_t scan_cpus_in;



/*

 * Simplified cpu sibling rendezvous loop based on microcode loader __wait_for_cpus()

 */

static void wait_for_sibling_cpu(atomic_t *t, long long timeout)

{

	int cpu = smp_processor_id();

	const struct cpumask *smt_mask = cpu_smt_mask(cpu);

	int all_cpus = cpumask_weight(smt_mask);



	atomic_inc(t);

	while (atomic_read(t) < all_cpus) {

		if (timeout < SPINUNIT)

			return;

		ndelay(SPINUNIT);

		timeout -= SPINUNIT;

		touch_nmi_watchdog();

	}

}



/*

 * Execute the scan. Called "simultaneously" on all threads of a core

 * at high priority using the stop_cpus mechanism.
@@ -165,6 +188,8 @@ static int doscan(void *data) 
	/* Only the first logical CPU on a core reports result */

	first = cpumask_first(cpu_smt_mask(cpu));



	wait_for_sibling_cpu(&scan_cpus_in, NSEC_PER_SEC);



	/*

	 * This WRMSR will wait for other HT threads to also write

	 * to this MSR (at most for activate.delay cycles). Then it
@@ -230,6 +255,7 @@ static void ifs_test_core(int cpu, struct device *dev) 
		}



		params.activate = &activate;

		atomic_set(&scan_cpus_in, 0);

		stop_core_cpuslocked(cpu, doscan, &params);



		status = params.status;
@@ -270,28 +296,6 @@ static void ifs_test_core(int cpu, struct device *dev) 
	}

}



#define SPINUNIT 100 /* 100 nsec */

static atomic_t array_cpus_in;



/*

 * Simplified cpu sibling rendezvous loop based on microcode loader __wait_for_cpus()

 */

static void wait_for_sibling_cpu(atomic_t *t, long long timeout)

{

	int cpu = smp_processor_id();

	const struct cpumask *smt_mask = cpu_smt_mask(cpu);

	int all_cpus = cpumask_weight(smt_mask);



	atomic_inc(t);

	while (atomic_read(t) < all_cpus) {

		if (timeout < SPINUNIT)

			return;

		ndelay(SPINUNIT);

		timeout -= SPINUNIT;

		touch_nmi_watchdog();

	}

}



static int do_array_test(void *data)

{

	union ifs_array *command = data;